Add API::V1::JobsController
ResponsesController#generate_excel returns the ID of the job as well.
Add a route for JobsController#alive
Poll JobsController#alive to see if the excel has finished generating.
Messed up the order of arguments and `=>` for defining a coffee script function.
Change `id` to `@id`.
Keep polling while alive.
Don't delete files uploaded to S3.

- Was creating an infinite loop
- Use S3s Object Expiration to delete excel files after a day. (http://docs.aws.amazon.com/AmazonS3/latest/dev/ObjectExpiration.html)
Remove the `excel_save_path` method. Is not used now.
Add a spinner to the excel dialog.
Make the excel dialog modal.